Add a test where a local variable has the same name as a property

compiler/testData/diagnostics/tests/smartCasts/implicitThisOrLocalVar.kt

@@ -0,0 +1,26 @@
+class Box(var item: String?)
+
+fun <T> take(it: T) {}
+
+fun Box.test() {
+    val other = Box("")
+    myRun {
+        if (item != null) {
+            take<String>(<!SMARTCAST_IMPOSSIBLE!>item<!>)
+            other.item = null
+            take<String>(<!SMARTCAST_IMPOSSIBLE!>item<!>)
+            this.item = null
+            take<String>(<!TYPE_MISMATCH!>item<!>)
+        }
+    }
+
+    var item: String? = "OK"
+    myRun {
+        if (item != null) {
+            this.item = null
+            take<String>(<!DEBUG_INFO_SMARTCAST!>item<!>)
+        }
+    }
+}
+
+fun myRun(block: () -> Unit) {}